Electric switch



Nov. 1, 1938. H, J HAMMERLY 2,134,717

ELECTRIC SWITCH Filed Dec. 51, 1937 2 Sheets-Sheet 1 lSll Llll

' INVENTOR ilmwfleffidimner Z z/ BY %3RNEY NOV. 1, 1938. H, J, HAMMERLY 2,134,717

ELECTRIC SWITCH 7 Filed Dec. 31, 1957' 2 Sheets-Sheet 2 INVENTOR flemmmljwwmergy 1 RNEY Patented Nov. 1, 1938 UNITED STATES ELECTRIC SWITCH Herman John Hammerly, New Britain, Conn, as-

signor to The Trumbull Electric Manufacturing Company, Plainville, Connecticut Conn., a corporation of Application December 31, 1937, Serial No. 182,672

12 Claims.

My invention relates to knife blade switches and especially to those having hinged blades.

The main object is to protect the switch against damage from arcing by reducing the possibility of arcing.

A special object is to provide simple and inexpensive means for this purpose.

Another object is to provide arc preventing means which can be readily removed for inspection and replacement of the stationary switch contacts.

In its preferred form the invention contemplates an insulating base for supporting the stationary contacts and terminals and the movable blades or switch members. This base is provided with upstanding walls with recesses or passages between them in which are mounted circuit terminals and stationary contacts in line with the switch blades.

An L-shaped guard is secured over these walls to partially enclose the switch contacts. These guards are slotted for the passage of the switch blades. I also preferably provide transverse barriers between the adjacentlwalls and separating the stationary contacts from the binding posts of the line terminals. A ledge is also preferably provided along the foot of the guard.

The invention is illustrated as applied to an enclosed switch with quick-make and break mechanism but the invention is not limited to such structures.

Fig. 1 is a front view of a switch embodying the preferred form of my invention in a switch box, the cover being open and parts broken away and parts in section. I I

Fig. 2 "is a vertical sectional of the line 2--2 of Fig. 1.

Fig. 3 is a horizontal section of the switch mechanism on the plane of the line 33 of Fig. 1.

Fig. 4 is an exploded perspective view showing the principal parts of the invention.

Fig. 5 is a front view of a simpler form of the invention, parts being broken away and shown in section.

Fig. 6 is a vertical section on the plane of the line B-6 of Fig. 5 showing the switch blade in the open circuit position.

Fig. 2 is a horizontal section on the plane of the line 'l-l of Fig. 5;

Fig. 8 is a perspective view of the guard memher.

The switch base 9 is of insulating material and secured in the box I II by screws H, II. The cirview on the plane cult terminals and binding posts l2 and 13 may be of any suitable form. The switch contact jaws I4 are secured to the terminals l2. The switch blade member I5 is hinged to the post RE which is connected to terminal l3.

The blades are actuated in any suitable manner for instance by the crank I'I, handle l8 and quick-make and break mechanism IQ of any suitable type. The base has side walls 20, 20 and intermediate walls 2| 2| (for a three wire system). Between adjacent walls are longitudinal passages or recesses 22, 22 in which the contacts l4 and terminals H for each circuit are located so that they are separated from each other.

The transverse barriers 23 of insulation are detachably mounted in grooves 24 in adjacent walls and extend down to the terminal plates be- I tween the binding posts and the respective stationary switch contacts. A transverse rib 25 extends across the base between the side walls and beneath the'switch contacts. A guard member consisting of a horizontal top plate 26 and a vertical lower plate 21 is provided. This may be made of a single piece of insulating material in L-shaped section and have the top plate mounted on the outer surfaces of the walls or partitions 2|, 2| and extend between the side walls 20, 20 so as to largely enclose the stationary contacts.

This guard serves to hold the barriers 23 in place.

and to snuff out any which tend to form when' the circuit is broken. The barriers 23 prevent damage to the binding posts I 5 and to the conductors. In case of need the guard members and barriers can be readily removed for inspection and repair.

In the form shown on the second sheet of drawlogs, the base 30 and the piece 3| carry the conducting parts and are suitably mounted in the box 32. The circuit terminals 33 and 34 are suitably secured to the insulation. The fuse clips 35 and 36 are also secured to the insulation in any suitable manner for receiving fuses such as 31.

, The stationary contacts 38 are adapted to receive the movable ends or tips of the switch blade members 38. which are hinged to the posts 4. which in turn are connected to the fuse clips 35 in the usual manner.

The movable switch members are actuated in any suitable manner for instance by the crank 4i, handle 42 and quick-make and break mechanism 43.

The base has side walls 44, 44 and the intermediate walls 45, 45 (for a three wire system) the block or base 30 is secured to the box by one or more screws such as 46. Between adjacent walls are recesses or passages 41 in which the stationary contacts and the respective circuit terminals are mounted so that adjacent contacts are separated from each other and adjacent terminals are also separated from each other.

The guard is of L-shaped section having a top plate or flange 5| and a lower plate or flange 52 and is held in place removably on walls 45, 45 by one or more screws 53. The ends of the guard may also be supported in grooves 54 in the side walls. The walls 45 may have projections 55 extending between adjacent switch blades. The guard is slotted at 58 to fit the projections 55. A rib 57 projects from the base just below the edge 52 of the guard so as to afford additional support for the guard and to assist in stopping arcs.

The guard is slotted at 58 in line with the paths of the switch blades so as to provide a minimum clearance and thus tend to prevent the formation of arcs when the circuit is opened. These slots may be formed in any suitable manner for instance by milling or cut ing in the proper places. When the guard is in place it completely covers the stationary contacts but may be readily removed for inspection and replacement of the stationary contacts and the terminals.

I claim:

1. An electric switch having an insulating base with upstanding walls and longitudinal recesses containing terminals and switch contacts between the walls, hinged switch blades adapted to coact with the contacts and a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending toward the base and having its slots in line with the switch blades.

2. An electric knife blade switch having a base with upstanding walls and recesses containing switch contacts and terminals between the walls, hinged switch blades adapted to coact with the contacts, a slotted insulating guard having one flange extending along the tops of the walls over the switch contacts and another flange extending toward the base and having its slots in line with the switch blades, and an abutment shoulder on the base overlapping the lower edge of the guard.

3. An electric knife blade switch having an insulating base with upstanding walls and longitudinal recesses containing terminals and switch contacts between the walls, switch blades adapted to coact with the contacts, a slotted insulating guard having one flange extending along the tops of the walls over the switch contacts and another flange extending toward the base and having its slots in line with the switch blades, and transverse insulating members between adjacent walls and between the switch contacts and their respective terminals.

4. An electric knife blade switch having a base with upstanding walls and recesses containing switch contacts and terminals between the walls, switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending adjacent the base and having its slots in line with the switch blades, a shoulder extending between the guard and the switch blades and transverse insulating members between adjacent walls and between the switch contacts and their respective terminals.

5. An electric knife blade switch having an insulating base with upstanding walls and iongitudinal recesses containing terminals and switch contacts between the walls, hinged switch blades adapted to coact with the contacts. a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending to the base and having its slots in line with the switch blades, and transverse insulating members between the walls and between the switch contacts and their respective terminals.

6. An electric knife blade switch having an insulating base with upstanding walls and recesses containing terminals and switch contacts between the walls, switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending to the base and having its slots in line with the switch blades, transverse insulating members between the walls and between the switch contacts and their respective terminals and an insulating top plate extending over all of the upstanding walls.

7. An electric knife blade switch having an insulating base with upstanding walls and iongitudinal recesses containing switch contacts and terminals between the walls, switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having an upper flange extending over the switch contacts and another flange extending toward the base and having its slots in line with the switch blades and a top plate extending over the upper flange of the guard and over the walls.

8. An electric switch having an insulating base with upstanding walls and longitudinal recesses containing terminals and switch contacts between the walls, hinged switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having one flange extending over the switch contacts and the other flange extending toward the base and having its slots in line with the switch blades and an insulating abutment shoulder on the base overlapping the lower edge of the guard.

9. An electric knife blade switch having an insulating base with integral upstanding walls and recesses containing switch contacts between the walls, hinged switch blades adapted to coact with the contacts and a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending to the base and having its slots in line with the switch blades.

10. An electric knife blade switch having an insulating base with upstanding walls and longitudinal recesses containing switch contacts and terminals between the walls, switch blades adapted to coact with the contacts and a slotted insulating guard of L-shaped cross section having one flange extending over the switch contacts and the other flange extending to the base and having its slots in line with the switch blades and transverse barriers detachably held between adjacent walls over the terminals.

11. An electric knife blade switch having a base with upstanding insulating walls and longitudinal recesses containing switch contacts and terminals between the walls, switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending toward the base and having its slots in line with the switch blades, an abutment shoulder on the base overlapping the lower edge of the guard and transverse insulating barriers detachably held between the contacts and the terminals.

12. An electric switch having a base with upstanding insulating walls and longitudinal recesses containing switch contacts and terminals between the walls, hinged switch blades adapted to coact with the contacts, a slotted insulating guard of L-shaped cross section having one flange extending along the tops of the walls over the switch contacts and the other flange extending to the base and having its slots in line with the switch blades, transverse insulating barriers between the terminals and the switch contacts and an abutment shoulder on the base overlapping the lower edge of the guard. 

